Air operated gun



Patented May 2, 1959 UNITED STAT [MR` GPERATED GUN Archie A. Johnson, St. Louis, Mowassignonto;

Harry ltillavies, StLonis, Mo,

Thisinventionerelates Ato improvements in air operated guns, and more particularly topneumatically actuated arms, whether of rifle orV pistol type,.in which the projectile is impelled by a charge of air-.or othennuid, preferably,- but not necessarily, froma constant source of iuid supply.

During the past-severaloyears numerous designs of -air operated guns have been proposed, principally for practice andttrainingpurposes, and general target work, as for use in shooting galleries and practiceranges. Only a few of such designs` have either-attainedi-or remained -in a status of` commercial success for any length of tima-and. as far-asis. known-al1 ofthe models heretofore.commerciallyoiiered have been characterized by complicated mechanism and a requirement of frequent service attention andadjustment.` None ofthe pneumatic guns as far as islknown, has heretofore attained the dependability in` servicewl'iich` characterizes rire arms, such Vas rifles or pistols of the types employing' cartridges and explosive propellantcharges. The present design is the result of` a number of months of careful experimentation, and a reasonable period of successful commercial use, from which itis clearlyapparent thatthe present design overcomes many if not all of the many objections to.. former i types of` pneumatic; practice arms.` This accordingly iormsa major and general objective of the `present` invention.A

Afiurther and important object or the invention is attained in-a simplified,- rugged, dependable, practically-service-free design-of pneumatic rifle or pistol, and one Whichmay be `used for-protracted periods, even through many thousands of rounds of ring without requiring any service attention.

Yet another object of the invention is attained in an improved air-cookingmechanism in which the propulsive iiuid, ai;1 for example, is employed in an exceedingly Ysimpliiied mechanism, for the dual purposes of shot propulsion and of recycling duce `machine Work Y in production;` which "maires for an unusual ease ofassem-b1y,and ease of servicef attention when required,` which `conduces as welLto light weight, andunusually good balance,` particularly when theimprovements are. eina ployedin agunwhichtis supplied with an air line or thelike, connectedto a constant source of` air under pressure.`

which:

Fig. l isa vertical longitudinal sectional eleva.. tion in` a planeincludingthe axis of the gunbore,

andshowing thefgeneral arrangement of oper-V ating mechanism and parts;

2 is asectional elevation taken in a hori zontal` plane, and showing certain of the elements:

as same would appear when viewed along line 2-2 of Fig. l, looking in the direction of the ar-.

rows, and

Fig. Sis anisometric View of an air-throttling disc, which serves alsoas a head element for the` i ringvalve cylinder.

Referring now by characters of reference to the drawing, the breechstructure comprised primarily of Vmajor parts iii and` il, is: shown only in those portions essential to illustrate andvdescribe the. present improvements, the-forepart of the barreLthestock and'other parts being omitted as unessential toa full understanding of present improvements. It should further be-noted that both the pneumatiovandmechanicalfeatures of the gunsV are adapted for use-in many types of practicearms, particularly in both pistols and riesof semi-automatic or automatic type.

Referring iirst .to the i'lre control mechanism and immediately appurtenant-elements, there arel provided at. therear of thebreechstructure lil and ii,l preferably apair of dowel `elements .|2-

which interni; with suitable recesses in the `stock (not shown). For securement or the breech structure `to thestock,` an extensionrod or bolt i3 is.` employed. Facultativo control ofV iire is efiected through a trigger lsl,..aboutwhich is a trig.`

ger guard i 5., the trigger being pivoted on a cross pin Iii `and pivotally connected through a pin i1" to a lever Ellfthe latterbeing pivotally supported.`

by a cross pin in thebreech mechanism. The

lever 2D1has a camming action on a projecting tail `piece 2i oi the sear\22,ithellatter being pivoted by Vmeans of -a crosspin 23, and being biased, downwardly-in Figrl, by -aspring 24 disposedgin a suitable drilled socket in element lc, and bearavioneta ing against and internally of a spring cup 25, the latter engaging the upper surface oi sear 22 as will be apparent.

rfhe downwardly presented shoulder on sear 22, shown at 2t, serves when the mechanism is in cocked position, to abut an annular shoulder of a perimetric projection El at the rear end of a combined bolt and piston element Internally of the bolt is a bolt spring of relatively heavy coil compression type, and shown at 3l. In assembiy this spring is positioned in part by a pin 32 which is of slightly less external diameter than the internal diameter oi spring 3l, and so serves as a guide and positioning element for the spring. The pin is mounted by projection oi its rearmost end into a socket 33 formed in a rear block element 3d and retained in the socket by a pin S5. It is a preference, as shown, to form the socket of slightly larger diameter than the end of pin 32 received therein, in order to permit a slight accommodating movement of pin 32. This has been found conducive to prevention of any cramping or binding of the spring or pin, within the hollow bore of the bolt and piston piece 3c.

Y The action of the rire control mechanism will be at once apparent, following the foregoing description of its parts, but it may be noted that lever 2li is normally biased forwardly as by a spring 36 anchored, as shown, to lever 2@ at one end and secured to a Xed pin at its opposite end. lAssuming bolt 3@ to be in cocked position as shown, and bolt spring 3| under compression, it will be obvious that rearward movement of trigger lll, as for nring, will lift the rear end of the trigger, and through its connection by the pin il to the lever 2G impart a lifting movement to lever 25. The latter coacting in camming engagement with the sear tail 2i, will actuate sear 22 about pivot 23, and as soon as shoulder 26 clears the projection 2l' of the bolt, the bolt will be impelled sharply forwardly by the spring. Upon return of the bolt to cocked position, this being brought about by air pressure as later described, it will be obvious that the projection or shoulder 2l will ride under the wide part or" Sear 22, and that upon full return of the bolt upon recycling of the mechanism, the sear will be depressed by spring 2d, retaining the bolt until a subsequent trigger pull.

Proceeding now to the more strictly pneumatic elements of the mechanism, it will readily appear from Fig. 1 that practically all elements of the gun except the ring mechanism per se, are carried in a pair of parallel bores, the upper of these being generally referred to as containing a gun barrel il@ the breech end of which is set into a bore di in breech element It. The second such bore, formed largely in breech element i l, is indicated at 42. It is preferred for compactness to align the air pressure mechanism as rar as possible in the bore 2 and to keep this bore as close as possible to bore lll. Identied either with an end or as an extension of bore 42, there will first be noted a cylindrical container 63, threaded as at ill into the breech element Il. Although air or other fluid under pressure may be supplied to the chamber in the receiver 13, it is preferred to provide an air connection 45 connected through a lexible tube (not shown) to an air tank or other source of supply. Proceeding inwardly of the bore d2, a portion is indicated at d5, which contains a firing valve cylinder dl, the diameter of which, as will appear, is appreciably less than the diameter of the surrounding portion of bore i2 so as to provide longitudinal air passages c which 4 are directed from the discharge end 5i of the receiver to a bevelled valve seat 52. rThis seat, except at times of iirmg, is closed by a piston valve shown in the form or a hardened steel ball 53.

Formed as a separable part of, but immediately associated with the cylinder 4l' is a throttling disc 5d provided with a restricted central aperture 55, which establishes, as is now apparent, a passageway for air from the end 5l or' the receiver to the space or chamber Within cylinder ill. It will appear that air under pressure will normally fill cylinder fil behind the valve 53, and that this pressure will be substantially the same as that maintained in the receiver 43. Retention of the cylinder head or disc 54 in position between the cylinder body di and the end of the receiver structure, is accomplished in part by the provision of spacing ngers, several or" which are provided, and indicated at 55. The passages 5i; intervene the several fingers 5B so that the latter constitute no appreciable obstruction to free flow of air from the end Eil of the receiver around the cylinder 4l.

Although the piston valve 53 is shown, as preferred, in the form of a hardened ball, and may consist conveniently of a steel ball'bearing element, the piston valve may with good results also be formed as a cylindrical element (not shown), one end margin of which is bevelled to conform to the valve seat 52.

The primary or major air passage for delivery of the propulsion air charge to the firing chamber, as will appear, includes passage portions 5l, Ell and valve seat 52 as thus far described, the end of cylinder l? in the region of the valve being apertured so as to permit of free passage of air through the valve seat, the apertures being indicated at 5l. Beyond the valve seat 52 the primary air passage is continued axially of the lowermost bore, through a short passage portion 6?, and beyond this zone the principal air passage is continued through a short vertical passage generally indicated at 6 l, whence air is conducted directly to the firing chamber 62 formed in the rear end of the barrel tube 40. In the region of the firing chamber, the tube 4B is conveniently secured as by a set screw 63 in the bore 4I of breech element lll.

In the example presently illustrated, it is contemplated to employ pressure from a relatively constant air supply source, such as a compressor tank (not shown) and to employ as shot, steel spheres such as small ball bearings, indicated at B. In utilizing rounds of this form, a supply of shot is retained by the magazine structure later to be described, and is fed therefrom, as later described, into the forward end of the firing chamber. In order to position the round in the rear of the bore of barrel Il@ prior to its propulsion, there is provided a forward shot stop, best seen in Fig. 2 as preferably consisting of a ball element Gil releasably retained in an aperture somewhat too small to pass the ball completely, by a spring 65 retained by a threaded plug 66. A rear shot stop consists of a cross pin, shown as vertically disposed, and indicated at 57. The firing chamber may be considered as that portion rearwardly of stop 64 in the tubular barrel element 46.

The bore 42 has an axially drilled plug element 'lil iiXed therein just rearwardly of said cylinder 41. This plug element is in abutting relation at its rear with an annular shoulder formed in said bore, and its foremost end abuts the cylinder sleeve lil, the head element or disc 54 of which atomare 5 abutslthe bevelled end'offthe'receiver 43, so that, upon threading the receiver element 43 into member Il, as at 44, there are positioned in assembly the cylinder .sleeve 41, its head 54 and theplugielement 10.

The plug piece Til is-transversely drilled through one of its wall portions to communicate with and provide a continuation `oi .the passageti. Thus -themajor or primary airpassage for the propulsion air charge is now seen to include ports or passages 5l, 5i), '52, '5B and 6i, and to terminate in thelfiring chamber 62.

`Besides forming certain portions of the air passages `as described, the plug lil is drilled or otherwise aperturedlor boredto provide a plu- 'rality, two of which are shown, of relatively smaller passages 7i.. It is preferred that the aggregate cross sectionallarea of passages 'il be somewhat less-thanthe `smallest sectional area of the major air passage, sc-'as to provide for a rela tively reduced and somewhat delayed now of air through passages ll, which, as will now appear, are directed into and serve at the time of opening of valve 53 to supply air to a cylinder constituted of a rearmost portion of the bore 42, and in which the boitll, as will readily appear, may be lapped, and operates asfalpiston between limits, the rearmost of which is `in its cocked position as shown (Fig. l), and the forward limit identified with a position just short of plug le. The plug 'lil serves a further purpose, in that it is centrally or axially drilled or otherwise provided with a bore 'i2 of such a diameter as to receive and to provide a slidable working clearance with an impact pin or iiring pin 73. This latter is preferably provided with blunt end faces as will appear, and the end faces are somewhat reduced in diameter as shown. The pin or impact element i3 is mounted in floating relation between the vaive 53 and the end face of the piston-bolt structure 3U, and its length is appreciably less than the distance between these elements when the valve is closedand the piston bolt is in cocked position, as shown.

Referring now to a simplified and preferred form of shot magazine adapted to retain a substantial number of rounds, the shot or projectile B, as has been brielynoted, will be fed into the firing chamber between pin Si and shot stop 64, and by preference foroptimum angle of introduction of each of the rounds to firing position, there is provided a widely or gradually curved elbow end of the shot feed passage, indicated at 7, this passage being formed in a small block element and the barrel sieeve 4U being drilled to provide a slightly reentrant or backturned portion constituting the terminus of the shot magazine, as indicated at i6. Rearwardly of and feeding into the elbow passage 74, is a magazine tube 'Il which is provided over the forward portion of its length with a narrow lateral slot (not shown), to accommodate a finger piece 8D and a projection 8l thereon, both of which are conveniently formed as part of the shot abutment 82. This latter is provided with a tail projection 83, to which is secured a somewhat flexible but only slightly compressible magazine spring of coil type shown at 84, this latter' being of a diameter just slightly less than the internal diameter of tube 7l. The spring 84 continues rearwardly to a lockout device shown as consisting of a nodular element in the nature of a cam 85. The piece 85 is provided with front and rear projections, to the former of which is securely anchored the end of spring Manci tothe latter ofwhich is iii) automaticallymaintained anchored a second magazine spring 86, which `functionally serves :as fa continuation of'springkSL The tube 'l'iandzspring 8S mayrbe continued rear wardly for a lengthconsistent with `the desired shot capacity ofthe magazine, and may, if desired, be extendedback into a chamber or bore portion `of the stock `(not shown).

It being understood .thatFig 2 is taken in a rhorizontal plane, looking upwardly, there will now She described lthe `function ofthe lockout device, `including .the projectinn 85. In FigfZ the maga- .zine is shown as empty, or substantially so, at any rate requiring replenishment Aprior to further Voperation of theigun. Pivoted on a short vertical rpinfii isa camminglever 9i) shaped so that it may at times-extendlintoua lateral slot 9| of the adjacent portion of themagazine tube 1l, into which slot the lever 9i! is lnormally biased as lby 4a spring :92. When, however, the magazine is exhausted of shot to theextent` that theprojection i515, acting; on the camming surface of lockout lever tt, forces this lever' upwardly (as shown in `Fig.i2) the lever end overrides sear 22, thus preventing the normal 'firing fand lifting movement of the .v Sear, until the projection 85 is again brought out of the path of lever 90. The action of the magazine and its function will have become apparent, but it may be noted .thatthere is provided a suitable loading port (notishown) near Vthe outer .end magazine tube 7T, and that loading is `effected by insertiomsay with the aid of a loading tube directed into saidport, ofthe predetermined number of rounds. incident to loading, linger piecedii-Si is retracted as Lthe rounds are fed into the. magazine and after insertionof the first one or two balls, projection B5 again Aclears the lever Sie, being forced rearwardly in the `tube '57. When the magazine is lledjnger piece eS-3l is released, .the magazine feeds the first round, and thereafter in order the succeeding rounds, each `into position in the ring chamber between pin {'l and shot stopl 5G. As each succeeding shot is iired by admission of the air charge in a manner to be described, the pressure of springs and B@ continues the feeding of the shot, one at a time, into ring position.

rfurning now to the control of admission of the .primary air charge, and of the utilization of air pressure for controlling the time of opening of valve 53 and further in effecting the recycling or cooking action through piston 3S, it will be assumed for illustration that there is a relatively constant, predetermined air pressure in the chamber of receiver 43. This pressure may be in the `compressor tank (not shown) by well known'pressure switches, or other means. `According to desired rapidity of ring, sizeof shot, and desired shooting conditionathe air pressureis desirably maintained say within therange-ofwlllbl'p. s. i.,but such range is not to betaken as critical.

`Assuming now that the bolt is in cocked position Vas shown, there lwill exist in the receiver 43, in passage or passages 5U, and in the cylinder 4?, air under substantially the pressure of' that in the receiver. Upon rearward actuation or pull of trigger i4, the bolt 30 will be released and sharply propelled forwardly by the spring `3 II.

The ring pin or impact element 'i3 may assume a position either in, or between either of the extremes of its possible movement. It will now be obvious that, irrespective of its axial position, the pin 'i3 will be sharply `struck by the end face of bolt vdi), and Awill in turn `make impactingcontactwithfthevalve 53;-Whereupon the pisiv o ton valve will be driven sharply forwardly (in the direction shown) over all or part of the internal length of cylinder lll. Because of the impact energy received by and imparted to the valve, a rst result will be a partial or nearly total displacement of air from the cylinder ll outwardly through the throttling opening 55. Valve 53 now being open, air will be delivered rapidly from the receiver port l through the annular passage spaces 50, thence through ports 5l, thence through seat 52, and passageway til- 6l into the ring chamber and will rapidly impel the round B out of the bore. In moving forwardly of the iiring chamber into the bore of the barrel, the shot will obviously displace (slightly upwardly in the direction shown by the drawing), the yieldable shot stop dal. Immediately this is done, the magazine structure, by reason of the bias of springs 84 and 86, will deliver the succeeding round to the iiring chamber.

Shortly following the rst rush of propulsion air through the major air passage or channel as described, two events ensue: One of these consists in the relatively rapid, although somewhat delayed restoration of full receiver pressure in,

with consequent complete filling of cylinder d1. Immediately following the expulsion of at least some of the air from this cylinder upon unseating of valve 53, the throttling passage will again admit air to the cylinder, although not erably reduced due to the partial conversion of :f:

head to velocity, in this region. Accordingly after a very short time, cylinder l? becomes refilled, although with some delay, and valve 53 is again seated. The selection of area of a trickle passage or bleeder port 55 will thus be of effect in determining the time during which valve 53 remains open for admission of the iiring charge of air. It is accordingly possible, by selection of different head discs 54, with diierent sizes or numbers of openings, to adapt the gun to the air supply pressure desired to be maintained and secondly, assuming a given or fixed air pressure and a bolt spring 3i of given loading characteristics, control o1" firing rate of the gurl may be effected within reasonable limits by the selective insertion of differently apertured discs 5e. l't will now have appeared that the passage 55 constitutes, functionally, a branch of the main passage directed to the firing chamber.

At about the time of admission of the firing air charge via valve 53, it will have been noted that a portion of the air transmitted by the principal air passages aforesaid, will be diverted through a second branch passage or plurality thereof, as indicated at il. Thus, practically at the time of or almost immediately following the admission of the iiring charge to the chamber 62, the air finding its way through the throttling passages ll, will replenish the supply ci air in cylinder space 42. This air, acting against piston 3S, will again compress spring l, and, under normal conditions, will recycle the gun mechanism in restoring the bolt-piston to cocked position. If it be desired to machine gun the arm, this may be done, among other ways, by blocking oir or restricting some of the passages ll so that the supply of air, or the effective air pressure in cylinder space t2, is inadequate fully to cock the piston. Under these conditions, although not intended as normal operation in a gun of this type, it is quitepossible vto maintain continuous firing throughout the magazine supply by maintaining pressure on trigger I4.

It may be noted that upon iiring the gun as by the described release of bolt and piston member Sii, the charge of air in cylinder 42 ahead of the piston face is not normally wasted, in fact adds materially to the quick delivery of the air charge into the firing chamber. It will be seen that this air charge must be expelled ahead of the rapidly moving piston, and is accordingly exe pelled through passage Si along with the onrushing iront of the air proceeding through passage lili. It is believed quite possible that there thus exists a very brief period in which actual pressure within passages til-6l and iiring chamber S2, actually considerably exceeds the gauge pressure of the receiver 43.

it will have been noted that in the structure described, there has been attained an exceedingly simple mechanical firing mechanism consisting only of trigger l, lever 2G, sea-r 22, and the piston bolt. These parts are rugged, easily and simply machined, and require little service attention.v It will further have appeared that the entire pneumatic assembly is extremely compact, may be formed practically entirely of standard stock in the nature of tube, rod and plate stock. It will further have been noted that the entire pneumatic assembly is iree of springs, with minor exceptions, and in positions where spring fatigue is not an important consideration. The presently described arrangement of main and branch air passages, and the cylinder valve assembly, conduces to an -accurate and dependable control of valve opening, hence of firing conditions, all in keeping with the several objects ereinabove noted, and others implied from the description and function ci? parts.

Although the invention has been described by making particularized reference to a single selected embodiment, the detail oi description is to be understood solely in an instructive, rather than in any limiting sense, numerous changes being possible both in the parts and in their arrangement, without departing from the spirit and scope of the claims hereunto appended.

I claim as my invention:

l. in a pneumatic gun, an air receiver, bai'- rel having a iiring chamber, a cylinder mounted adjacent said barrel and provided with a bore therethrough having an intake from said re ceiver and a discharge into said firing chamber, a valve seat in said bore intermediate said openings, a valve movable in said bore and cooperable with said seat to control flow oi air between said openings, a trigger-releasa'ble movable piston in said bore and normally spaced from said valve, a in said bore and engageable by said piston to unseat said valve to permit air to flow from said receiver into ring chamber, air-iiow throttling means in said bore intermediate said air-receiver and valve seat and between said dis charge opening and piston and proportioned so that the greatest proportion ci the air iiowing from said air receiver flows into said ring cham-` ber.

2. In a pneumatic gun, a breech structure provided with a pair of vertically superimposed parallel bores, a barrel extended into said upper bore Vand provided ywith a firing chamber, said lower bore including an elongated air receiver, a major passageway rearwardly of said receiver, a hollow valve cylinder in the forward end of said passageway rearwardly of said receiver. longieV 9 tudinal air passages extending rearwardly along said cylinder and communicating at their forward end with said receiver, transverse air passages leading from the rear of said longitudinal passages into said cylinder, a head at the forward end of said cylinder and provided with a throttling passageway therethrough leading from said receiver into the interior of said cylinder, a valve seat at the rear end of said cylinder adjacent said transverse air passages, a piston valve movable in said major passageway to engage said seat to seal oil air ow inwardly from said transverse passages, hollow means forming a lateral extensien from said major passageway and opening into said ring chamber for propulsion of a round in the latter, an elongate impact pin longitudinally movable in said major passageway to engage and unseat said valve, a guide in said lowermost bore to slidably receive said pin and having a restricted air duct therethrough extending rearl0 jecting longitudinally into the latter, said impact pin being shorter than the distance between said valve seat and the adjacent forward end of said retracted combined bolt and piston.

ARCHIE A. JOHNSON.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 452,882 Giiard May 26, 1891 645,932 Beck et a1 Mar. 27, 1900 1,854,605 Tratsch Apr. 19, 1932 1,886,704 Loomis Nov. 8, 1932 2,006,030 Price June 25, 1935 2,101,198 Robinson Dec. 7, 1937 2,123,324 Webby July 12, 1938 2,238,384 Feltman Apr. 1.5, 1941 2,251,836 Schmidt Aug. 5, 1941 2,304,320 Tratsch Dec. i8, 1942 FOREIGN PATENTS Number Country Date 360,259 France Feb. 17, 1906 444,508 France Oct. 19, 1912 

